Inbreeding and the Origin of Races
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JOURNAL OF CREATION 27(3) 2013 || PERSPECTIVES time, they would eventually come to population at that time, it should be Inbreeding and the same ancestor or set of ancestors clear that there couldn’t be a separate the origin of in both the mother and father’s side of ancestor in each place. And at 40 the family. This can be shown using generations (AD 810) you would have races simple mathematics. over 1 trillion ancestors, which is Simply count up the number of impossible since that is more people ancestors you have in preceding than have ever lived in the history of Robert W. Carter generations: 2 parents, 4 grand- the world. Almost all of your ances- parents, 8 great-grandparents, 16 tors that far back are your ancestors frequent question asked of great-great-grandparents, etc., and thousands of times over (or more) Acreationists is, “Where did the factor in that the average generation due to a process I call ‘genealogical different human races come from?” time for modern humans is about 30 recursion’. There are various ways to answer this years.4 Thus, 10 generations ago was Indeed, it does not take many gen- within the biblical (‘young-earth’) about AD 1710, and you had 1,024 erations to have more ancestral places paradigm and many articles and ancestors in that ‘generation’ (Of in your family tree than the popula- books have already been written course, not all of your ancestors lived tion of the world. The problem is made 1 on the subject. However, I recently at exactly the same time, but this is worse when you consider that many thought of a new way to illustrate a good estimate.) By 20 generations people do not leave any descendants. the origin of different people groups (about AD 1410), you would have over For example, it is estimated that using the 12 Tribes of Israel as an 1 million ancestors living around that approximately 25% of the population example. time. At 30 generations (AD 1110), it of Iceland in the early to mid 1800s From the Genesis chronogene- would seem that you would have over are the ancestors of about 90% of the 2 alogies, we have a detailed family 1 billion ancestors. At least, that is the modern population, and the results history from Noah through Abraham, number of branches that far back in of earlier genealogical work is even and then to Jacob and his 12 sons. your family tree. However, since this more skewed.5 Simply put, the vast There is one significant person in is probably greater than the world majority of ancient people do not have this list, however, that serves as the most significant ancestor to the future Jewish nation: Terah, the father of Terah Abram. Terah was also the father of Abram Sarai Haran Nahor Sarai, though not by Abram’s mother (Genesis 20:12), Nahor, and Haran. Milcah It turns out that the four children of Terah are all ancestors of the 12 Tribes Bethuel of Israel.3 And it is this complex fam- ily tree that we can use to illustrate Isaac Rebekah Laban ??? ??? why different people groups across the world don’t all look the same Jacob Rachel Leah Bilah Zilpah (figure 1). Joseph Reuben Dan Gad The science that has rejected Benjamin Simeon Naphtali Asher ‘race’ Levi When dealing with different peo- ple groups, geneticists often calculate Judah a number called the ‘inbreeding Large grey boxes = unknown ancestry Small black boxes = unknown wives Issachar coefficient’ and talk about ‘identity Additional descent from Terah canenter at any grey box. by descent’ because every person has Zebulun inherited multiple identical sections of DNA from both sides of their fam- Figure 1: The genealogy of the 12 Tribes of Israel (at bottom) can be traced along multiple routes from Terah through all four of Terah’s named children. Large and small grey boxes indicate people ily. This happens because, if everyone of unknown ancestry. Additional descent from Terah can enter at any grey box, meaning that the was to trace their family tree back in numbers given in the text for percent similarity to Terah are minimum estimates. 8 PERSPECTIVES || JOURNAL OF CREATION 27(3) 2013 Table 1. Eight lines of descent from Terah to the 12 sons of Israel and the percentage identity to We have to be careful, however, when Terah’s genome expected at the terminal generation. trying to assign ‘race’ to a person, for modern geneticists have rejected Generation % Line the entire notion. As geneticist Lluis 0 1 2 3 4 5 6 Terah Quintana-Murci recently said: A Terah Abram Isaac Jacob 12 Sons 6.25% “But the genes that explain the B Terah Sarai Isaac Jacob 12 Sons 6.25% phenotypic differences between C Terah Nahor Bethuel Rebekah Jacob 12 Sons 3.13% populations [i.e., the differences in the way people from different D Terah Haran Milcah Bethuel Rebekah Jacob 12 Sons 1.56% populations look] only represent a E Terah Nahor Bethuel Laban Rachel 2 Sons 3.13% tiny part of our genome, confirming F Terah Nahor Bethuel Laban Leah 6 Sons 3.13% once again that the concept of G Terah Haran Milcah Bethuel Laban Rachel 2 Sons 1.56% ‘race’ from a genetic standpoint has been abolished.” 9 H Terah Haran Milcah Bethuel Laban Leah 6 Sons 1.56% Israel as a case study any living descendants. Conversely, family tree is shorter than this, the Genghis Khan (1162–1227) has calculations in this paper are probably Now, turning to the Bible and to about 17 million descendants alive accurate. That is, we would expect one particular family, that of Israel, today, including 10% of the 2 million him to be a genetic ancestor to the rest we can see these ideas at work. Most Mongolians and perhaps 0.5% of of the people in the genealogy. people with some knowledge of the the world’s population, or 1 out of The number of ancestors going Bible know that Abram married his every 200 people alive today!6 All back in time, coupled with many half sister Sarai, Isaac married his this means that the calculations in people not having children forward cousin Rebekah, and Jacob married the previous paragraph should be in time, coupled with the effects of assumed to be maximum times to recombination, coupled with the fact Table 2. The significant people in the genealogy get to the point where you have more that people historically have interbred of the 12 sons of Israel and their percentage identity to Terah. ancestors than the world population mostly within their own people at the time, because the effective group, means that there has been a Person Terah population size is much smaller that significant amount of inbreeding in Abram 50.0% the real population size. every population. One additional factor to consider is This is the reason that people from Sarai 50.0% that DNA is inherited in large blocks different people groups don’t look Nahor 50.0% of unequal size. This is due to the the same. Many genes for traits like Haran 50.0% recombination of homologous chro- height, head shape or even eye color Isaac 50.0% mosomes prior to sexual reproduc- don’t necessarily show strong inherit- tion. My own calculations (data not ance patterns. Yet, enough inbreeding Bethuel 37.5% shown) indicate that in as little as 5 has occurred in all people groups that Jacob 34.4% generations (that is, the mid-1800s) strongly associated traits often exist Milcah 25.0% you might have people in your family that can be used to roughly distinguish Rebekah 18.8% tree from whom you inherited no one set of people from another. This DNA! This depends on the amount is not always easy to do, however, Laban 18.8% of recombination per generation and and one can find almost all traits in Rachel 9.4% 7 the distribution and spacing of recom- almost all populations. In fact, when Leah 9.4% bination events. The various models looking at the underlying genes, there Bilhah ? I have applied all point to a rapid loss are about 10 million variations in the of genetic ancestors, irrespective of human genome that are found in all Zilpah ? genealogy, with an average of less world populations.8 These are not Wife of Haran ? than 10 generations to null ancestry found at the same frequency in all Wife of Bethuel ? for any ancestor-descendant pair populations, however, and this gives Wife of Laban ? in the genealogy. Because Terah’s rise to some of our ideas about ‘races’. 9 JOURNAL OF CREATION 27(3) 2013 || PERSPECTIVES his cousins Rachel and Leah, who Abram, because they had, in turn, and there are other indications in gave rise to 8 of the 12 Tribes of Israel. inherited identical parts of Terah’s the Bible. For example, the endemic But all these people also descend genome. In those places (about 25% gigantism in various groups liv- from Terah. Does this mean that a of his genome), any recessive traits ing in Canaan prior to the Israelite large fraction of Terah’s DNA should were fully expressed. conquest10 may have been due to a be represented in the 12 tribes due to In Israel’s family tree, multiple concentration of some gene(s) associ- inbreeding? generations intermarried. The ge- ated with gigantism in the population Children each inherit ½ of the DNA nealogy is complex. How can one through inbreeding. There is also carried by each parent.